Fundraising Improvement on multiple 'PayPal Instant Payment Notifications'

I've run into a bit of an issue with the fundraising form for paypal in that I already have a paypal ipn setup from another plugin.

Problem: The fundraiser plugin says:

In order for PayPal simple payments to log properly you must turn on PayPal Instant Payment Notifications and point it to: ...

Paypal only gives you one input box for adding a manual ipn. However, they do have a solution to make it a little easier, and the fundraising plugin should try to take advantage of this.

Why not just use Paypals own “notify_URL”? If this is used on button code the IPN you have set in your account will become null and use the url you specify in “notify_URL”.

According to their docs, it would help if the following was added to the template-functions.php file.

To set the return URL for a transaction, include the return variable in the HTML FORM:
template-functions.php line approx: 614

<INPUT TYPE="hidden" NAME="return" value="http://mywebsite.com/wp-admin/admin-ajax.php?action=wdf-ipn-return-paypal">

Reference:
Reference

Bottom line:
Instead of making me 'the user' go to paypal to insert the ipn, why not just use the paypal return_url input type and add that to the form?

Is there any reason not to do so?
(I'm not a paypal expert, just trying to solve this problem)